Over the past few decades, femtosecond (fs) laser excitation of magnetic materials has led to the discovery of a rich collection of physical phenomena.
Among these, single fs laser pulse all-optical switching (AOS) of the magnetization in rare-earth transition-metal ferrimagnetic alloys [1]}, [2]} and multilayers [3]}, [4]} appears to be especially promising for future memory applications [5]}.
This phenomenon was shown to arise from the transfer of angular momentum between two magnetic sublattices [6]}.
In the same period the fs laser excitation of spin currents, mobile electrons carrying spin angular momentum, has been gaining significant interest from a fundamental perspective [7]}, [8]}.
